Question

Why is my Mazda 3's AT (Automatic Transaxle) light on after an oil change?

Yesterday I changed the oil in my Mazda 3 from durablend to synthetic, and replaced my filter as well. I also added some 134a refrigerant since I was low. I noticed a little bit of fluid under my car after I drove away, but figured it was from the air conditioning.

While driving, I noticed some odd behavior in shifting and realized that the AT (Automatic Transaxle) light was on. I got home and let it go, thinking that the oil probably just needed to circulate through and it'd go away.

Today, I drove it once and it was fine-- no shifting problems or AT light. The second time I noticed weird shifting problems, the AT light, and the Transmission light were on.

What could be causing this? Would filling the oil a little above the "Max" line cause this?

What oil did you change? An engine oil change has nothing to do with the ATF fluid. There is no physical connection between the two and the only possible connection is that you may have inadvertantly loosened the AT drain plug during the engine oil change. In any event, check your ATF fluid level and make sure the fluid is at the proper level with the engine running and in the "park" position.

Did you figure out what was happening with this? I just did the same thing. I did a full oil change and changed filter and oil. Then had shifiting problems as I drove away and car was missing between 2nd & 3rd gear for a couple seconds every time. AT light also came on.